> If we would also change all ED into $D$EPREFIX inheriting prefix.eclass
> would do the trick entirely and we could merge back.

I missed the point here:
Is this because D (and ED) might be unset during ebuild source-time, so
setting ED in prefix.eclass' global scope will go wrong?
If yes, then +1.
/haubi/
--
Michael Haubenwallner
Gentoo on a different level